| 摘要 |
In order to establish a wafer evaluation technique for measuring the lifetimes of carriers in all semiconductor wafers when the semiconductor wafers are cut and manufactured from a semiconductor crystal ingot, the wafer evaluation technique being practical and more significantly improved in measurement speed, accuracy, device operation, and the like than conventional methods, the present invention is a method and device for evaluating the lifetime of free carriers (a general term for free electrons and free holes) within a silicon wafer (3). First, free carriers are generated (excited) by irradiating the silicon wafer (3) to be evaluated with a free carrier generation (excitation) laser beam (R21). Next, the silicon wafer (3) in which the concentration of the generated free carriers is non-uniformly distributed is irradiated with an observation laser beam (R11). An angle at which the observation laser beam (R11) is emitted after being transmitted through the silicon wafer (3) is measured. Consequently, the spread (half-value width) of the distribution curve (FD) of electrons and holes can be measured, thereby making it possible to evaluate the quality of the silicon wafer (3). |
